Synthesis and Cytotoxic Evaluation of a Series of Genistein Derivatives

Thirty genistein (=5,7‐dihydroxy‐3‐(4‐hydroxyphenyl)‐4H‐1‐benzopyran‐4‐one; GEN) derivatives were synthesized from genistein through a facile approach in high yields. Compounds 9, 11, 12, 23–30 were reported for the first time, while 13–22 have already been reported in our recent paper. The cytotoxic activities of these compounds were evaluated against a human nasopharyngeal epidermoid tumor cell line KB. Compounds 7–9, 12, 14, 16–19, 21, 24, 27, 29 showed remarkable antitumor activities in vitro, which was comparable with 5‐fluorouracil, an anticancer drug. On the basis of the obtained experimental data, structure–effect relationships were discussed.